Communication system



Dec. 8, 1931. w, BUMSTEAD 1,835,929

COMMUNICATION SYSTEM Filed April 25, 1930 INVENTOR RALPH w. BUMSTEAD BY g I ATTOR N EY Patented Dec. 8, 1931 UNITED STATES PATENT OFFlCE .BALPH w. numsrnmmr'wasrrmtn, NEW JERSEY, assmnoa '10 m'rrimurromu.

COMMUNICATIONS LABORATORIES INCOIB IPORATED, OF NEW YORK, N. Y., .A COR- DURATION OF NEW YORK MHIUNICATION SYSTEM Application filed April 25, 1930. Serial No. 447,205.

This inventionrelates to improvements in or connected with communications system disconnect and has for its main object to provide a selecting system or selector more particularly designed for use on telegraph way-Wire circuits, particularly those which are equipped with printing telegraphs or communications receivers. A further object of the invention is to render possible the employment of any printing telegraph keyboard or other impulse sending means as a transmitting selector to control-selecting means at any waystation on the circuit, thereby to single out any'desired printer as the receiving instrument, while other printers along the line are,

for the time being, disconnected,

The selecting system according to the present invention provides among other things the following advantages:

1. Availability of a wide range of code combinations amounting to as many as 512 permutations of long 'and short lmpulses even where the number of selecting impulses is limited to nine. 0 e 1 2. Interchangeability of receptive means, that is to say, to enable a selector at any station to be adjusted to respond to one or another code combination as may be desired.

3. Adaptability to the requirements-0f the selector system of certain equipment which is already standardized and incommon use for other purposes.

4. Utilization of the printing telegraph keyboard, or its equivalent, and -the usual line relay to send and receive a selecting signal as well as to operate the telegraph receiver after selection has been accomplished. 5. The facility with which one or any number of stations on a way-wire may be selected .and made receptive to communications, and

when it is desired that messages shall be received at a plurality of stations simultaneousnals for each particular station and as each receiverg-is connected it is not rejected .by

ithetransmiSSiOn of "a subsequent selecting signal, but all of the selected stations can be the perator.

d simultaneously at the will of.

Other advantages will become apparent as -the invention is described with reference to the accompanying drawing, which is a diagrammatlc view of the selector system according to the present invention.

In the preferred embodiment of this invention, as will be observed upon reference to the drawing, the line relay A receives the incoming signals at a given station and by the vibration of its armature against the contacts all of the associated apparatus is locally controlled both for the selecting operation, and for reception of communications after a selection has been made. The selector proper includes a source. of energy 20, connected with the contacts of relay A and with other parts of the apparatus as will be brought out more in detail in describing the operation of the device.

A slow-to-operate relay B, preferably of the dash-pot type is suitably connected so as to serve as a start relay to render the selector receptive to selecting signals and non-"- lugsand connecting straps serves to set up 'thearrangement of any code combination to'which the selector is intended to respond. Theins'trument. for reception of traflic such as a telegraph printer of usual construction is indicated at 35, and is adapted to be driven" by a motor 38, the power source for which is indicated at 49.. A special switching device H is symbolically indicated as an attachment to the instrument 35 to be co nv trolled thereby when it is desired to re-set the rotary switch after completion of a message transmission. Other details of the invention brought out in the following explanation of and. their. functions will be more specifically When on the marking side, after the desired station has been selected, relay tongue 14 completes a printer circuit at that station thus: positive battery 20, contact 15, armature 14, conductor 58-, switch segment 9, bridging wiper 51, switch segment 11d, conductor 37 and printer-selecting magnet 36 to ground. v It will now be shown how the bridging wiper 51 can be brought into cont-act with segments 9 and 11d in order to makeany desired printer receptive to traffic signals, for it is obvious that such reception depends upon moving the wiper 51 from the initial position in which it is shown over to the left extremity of the contact banks.

When there is no traffic on the line, armature 14 is held against contact 15 and, assuming that the selectors have all been restored to their initial position, only one local circuit remains at that time completed, namely, through a biasing coil 26- -25 in the relay C thus: positive battery'20, wntact 15, armature 14, conductor 57, resistance 34, and coil 26-25 to ground. Current passing through this coil in the direction given tends to hold the relay armature 17 to the right, against contact 18. s Q 1,

The selector is put into a receptive condition for selecting signals by first opening the line circuit or by transmitting a space-pulse of somewhat greater duration than any which are used in trafiic, say for two or three seconds or more, the time not being critical, thus throwingthe armature 14 against-the contact 16. When this is done, the dash-pot relay B operates in the following clrcuit: positive battery 2Q, conductor 55, relay B, rotary switch segment 1d, wiper 51, segment 0, conductor 58, armature 14, contact 16 to negative battery.

The operation of relay B closes contacts 40 and 41 so that the rotary switch magnet 45 will be energized in this circuit: posltive battery 20, conductor 55, contacts 40 and 41,

magnet 45, segment 6, wiper 50, segment 1a,

conductor 58, armature 14, contact 16. to

negative battery.

Both the dash-pot relay B and the rotary magnet 45 are de-energized upon sending a marking impulse over theline. At this moment wipers 50 and 51 are advanced to the second position, that is to say, to segments 22; and 2d respectively. -The construction of the rotary switch F is such thata wiper step takes place simultaneously with each deenergization of the rotary magnet 45;

After. the wiper .51 has made one step, the

ments are connected through conductors 52 dash-pot relay circuit will be kept open during the remainder of the selecting steps and during the reception of traflic signals at the selected, station, whereas, in making the selection, various transmitted impulses will re-' sult in the operation of the re-set magnets 46 at the stations to be rejected, so that the wipers of these selector switches will be re turned to their initial position where their dash-pot relays B can again be actuated on sending I a long space-pulse. It will be seen, therefore, that the function of relay B'is merely to providea circuit for the initial selecting impulse as required to actuate the rotary magnet 45, and to do this only after the prolonged space-pulse has been sent as an indication that subsequent signals are for selecting purposes rather than for traflic.

For the second and subsequent steps of the rotaryswitchF, the off-normal springs 42, 43 and 44 are broughtwinto play automatically by the wiper 50 on its first step and when in contact with one another they put positive potential on one end of each of the magnet windings 45 and 46 and also 0 the terminals 21' and 24 of relay CI 4 The. individual arrangement of connecting straps on the terminals G will be different for each selector at the different stations, SU

,that only one will respond to a given selecting code by making a complete excursion of its wipers over the rotary switch segments.

' The letter keys V, I and Blank have. been found most suitable for selector code 0 signalling because in thc'adopted 51-unit code the'letter V consists of one space unit contiguous with the starting unit and thereby provides a singlespacing signal of two units duration upon each key depression; the-letter I is represented by two such spacing signals separated by a marking signal also of two units duration; and the Blank key provides a spacing signal the duration of which is six units of time. The timed, 11o

spacing impulses when controlled for selectmg purposes by the keys V, I and Blank allow the selector switch to function at only one-half the speed which; is attainedby the character selecting magnet on the printer. The drawing shows an arrangement of the terminal straps suitable to receive' the code:

Blank -v I Blank Blank I (,Dot'Dot Dash Dot Dash Blank Dash DOtd'DOt Dash) This code consists preferably of nine space-pulses resulting from seven key-depressions. The dot signals have one-third the duration of the dash signals. The terminal groups designated 2- to 10 inclusive, are so arranged that as the wiper 50 makes its excursion over the contact segments 2a, 3a, etc., the rotary magnet 45 willbe energized fol.-

lowing'a spacing-dash-pulse where such seg- {s to the vertical terminal straps. The rotary magnet 45 will likewise respond after sending a spacing-dot-pulse where the segments are connected to horizontal straps acrossthe terminals. Furthermore, the selector will be rejected and re-set by any local impulse directed. through the re-set magnet 46 as. when the wiper 51 is in contactwith one of the segments 20!, 3d,.etc., leadin to a .horizontal strap following a spacing-dash-pulse or leading to a vertical strap following aspacing-'dot-pulse.

This arrangement makes it possible to use either a dot or a dash to advance the desired rotary switch and to utilize these same dots or dashes in rejecting and re-setting all other selectors on the line. V 1

The function of relay C will'now be explained so that the response of any selector to spacing dot and dash pulses may beunderstood. This relay is of the usual type employin four windings. The ,terminals of these'win ings have been given 'odd numbers to designate where positive potential should be applied in order to attract the relay armature 17 against its contact 19. The evennumbered terminals, therefore, when connected to positive potential will provide the proper direction of current in-the windings to attract the armature 17 against contact 18.

As previously stated, the first step of the rotary switch which follows a long space-- pulse causes the closing of contact springs 42, 43 and 44' of the off-normal s witch,and during the reception of selective signals the relay winding terminals 21 and 24 are con-- nected to positive battery. The position of line relay armature 14 'on the marking side (against contact 15) puts positive potential on terminal 22 and on the condenser D with which terminal 23 is also connected so that there is no drop of potential through winding 21-22 nor windin 24-23 until the line relay armature 14-shi ts to contact 16 connected with negative battery. At that instant, however, two opposing forces or momentarily set up in the relay windings. One circuit is: positive battery, conductor 55, offnormal switch springs 43 and 44, conductor 54, winding 21-22, resistance 32, conductor 57, armature 14 and contact 16 to negative I battery. The opposing .circuit is: positive to contact 19.

battery, conductor 55, ofi-normal springs 43 and 44, conductor 54, winding 24-23, resistance 31, rectifier or uni-directional conductor E, condenser D, conductor 57, armature 14 and contact 16 to negative battery. Current ceases to flow through the winding 24-23 as soon as condenser D becomes charged and at that moment the energization of coil 21-22 throws the armature 17 across It will be understood that the delay in actuation of the armature 17 can be accurately adjusted by the capacity of condenser D and by the resistance 31 so that a spacingdot-pulse-will never cause the armature 17 to leave contact 18 while aspacing-dashpulse 'will surely throw the armature 17 against contact 19. When the space-pulse is ended, armature 14 of the line relay is again thrown against the marking contact 15 thereby establishing. the following circuit for the discharge of condenser D, assuming that a spacing-dot-pulse was transmitted: condenser D, rectifier or uni-directional conductor" E, armature 17, contact 18, conductor 63, lower strap of terminal group 2, one of the conductors 52, segment 2a, wiper 50, rotary mag-' net 45, conductor 56, contact springs 42-43,

conductor 55, contact 15, armature 14, conductor 57 to negatively charged side of condenser D. The condenser charge is thus dissipated effectively for the purpose of actuating the rotary magnet 45 to'step the wipers over onto another set of segments.

If a rotary switch step is to follow a spacing-dash-pulse, then the condenser discharge will be directed through contact 19, conductor 62 and one of the right hand vertical terminal straps as shown at 4, 6, 7 and 10 in the drawing. In-this case a high-resistance shunt circuit is also established during the condenser discharge to lock the armature 17 against contact 19, thus condenser D, rectifier or uni-directional conductor E, contact 19, resistance 33,'coil 27-28 and conductor 57 to negatively charged sideof condenser leaving the biasing coil 26-25 to act alone in restoring the armature 17 to the right s de in readiness for a succeeding signal.

It will thus be seen that the rotary magnet 45 receives its operating pulse from the con-- denser D always at the moment of contact between line relay-armature 14 and its contact 15, but that this condenser discharge can be directed either through conductor 63 and any one of the lower horizontal terminal straps after a spacing-dot-pulse, or else through conductor 62 and any one of the right hand vertical terminal straps aftera spacing-dasli-pulse.

Furthermore, since the arrangement 0 terminal straps must correspond with the selecting signal for each station, re-setting of the unwanted selectors will be'accomplished thus: either a condenser discharge following a spacing-dot-pulsewill be directed through conductor 63 and a left hand vertical terminal strap or through conductor 62 ,and 47 .to ground.

and an upper horizontal strap following a spacing-dash-pulse. Either way the reset magnet 46 is energized by the condenser charge fed through one of the conductors 61, one of the segments 2d, 3d, etc., wiper 51, segment 7", re-set magnet 46, conductor 56," springs 42-43,conductor 55, contact 15, armature 14, and conductor 57 to condenser I).

The winding of the re-set magnet, it will be noted, has a centre tap connected with conductor 56, and one of the terminals of the winding connects with contact 48 against which armature 47 drawn when the magnet is energized. This grounds the upper end of the winding so that the magnet willlock itself in a circuit from battery 20 through conductor 55, off-normal switch springs 43, 42, conductor 56, re-set magnet, contacts 48, This circuit is broken at the off-normal springs when the rotary switch has been fully restored to normal. Assuming now that the remainder of the pulses have been transmitted necessary to select a station printer, the wipers 50 and 51 at the selected station will cogne to rest at the left hand end of the segment arc: wiper 5O bridging between segments 0 and 11a, while wiper 51 bridges between segments 9 and 11d. In this position current is supplied from the source 49 to the printer motor 38 through the conductors 53 and the switch segments 0 and 11a. The line relay armature 14 is also connected through conductor 58,

' segments 9 and 11d, conductor 37'and printer control magnet 36 to ground. The printer is thus placed in, service to respondto traflic signals as received by the line relay A.

Withno circuits now complete for the rapid discharge of condenser D, the relay C will have a tendency to become choked with its armature 17 resting against contact 19 during the reception of traflic signals. The only circuit now available for the discharge of condenser D is through the high-resistance winding 2728 which tends to hold armature against contact 19. This'des'irable feature will minimize the vibration... of armature 17 during the reception of trafiic signals when relay C has no function to perform. The loss of power dissipated in the coils of this relay and in the condenser. D is also a negligible factor so that it is not necessary to provide any circuit breaker'in conductor 57 to throw the relay C out of commission during tra-flic reception.

\Vhen it is desired to disconnect a printer that has beenin operation, the upperrc'ase-J key will preferably be depressed at the send 1 ing station. This causes a stunt-bar H on the printer to .close a. circuit which groundsthe [f e-set" magnet 46, causingthe latter to operto from battery potential fed to it through ductor- 56. This L'Q-SBt magnet,'it will be its own locking circuit to ontact 48 and armature, 47

in readiness to initiate a new reception of se-' lector signals. I

What is claimed is: I

1. In a communications system, a line relay, a step-by-step switch, a slow-to-operate relay controlled by the line relay and respons'ive to an impulse of at least a predetermined length to cause the switch to advance one step, receptive means thereafter responsive and differentiating between signals ,of relatively der said step-by-step switch operable upon reception of a predetermined combination of signals and to reject and restore said switch 10 its initial position upon reception of any other combination of signals. i

2. In a communcations system, a line relay, a signal duration ditferentiatingrelay and a resetting magnet for the switch operable uponreception of-any other code combination to reset the switch to normal position.

and short duration, and means to ren- 3. In a communications system, a line relay, a step-bystep switch, stepping and re setting electromagneticmechanisms therefor receivlng means to differentiate between varying characteristics of transmitted signals and to render the switch stepping and re-setting mechanisms selectably operable according as the received combination of signals'agrees or disagrees with a pre-arranged code, and operating circuits for the stepping and resetting electromagnetic mechanisms including contacts controlled the swltcn. 4. In a communications system, a line relay, a time element differentiating relay comprisinga plurality of windings, a condenser and a uni-directional conductor in the circuit of one of said windings, selecting means in a uni-directional circuit which includes said condenser and the contacts of said time element differentiating relay, and means'to advance or reset the selecting means upon discharge of the condenser.

5. In a communications system, the combination of a rotary switch comprising a rotary magnet, a wiper and contact segments associated with said rotarymagnet, a re-set magneQ-and a wiper and contact segments asthan of the predetermlned character are received to re-set the wipers to normal position.

6. A selector as set forth in claim 5 in combination with a communications receiver in which the final step taken by the rotary switch wipers establishes connection between the line relay and said receiver and renders the same receptive to' transmitted communications.

7. A selector as set forth in claim 5 in which the re-set magnet may be operatedat any of the steps taken by the'rotary switch wipers provided the received succession of V signals is intended to reject said selecting means.

8. In a communications system, a line relay, a start relay, rece tive means controlled by the line relay and ifferentiating between selective and rejective signals, a communications receiver, means controlled by the start relay for establishing connection'between the line relay and said receptive means, and

'an operative connection between the line relay and said communications receiver established by the receptive means in response to the selective signals.

9. A selector comprising a time element difi'erentiator comprising a relay in association with a condenser and uni-directional conductors and selective means rendered operable by successively charging and discharging said condenser.

10. A selector comprising a time element differentiator comprising a relay in association with a condenser, independent charging and discharging circuits therefor, selective means rendered operable upon the discharge of said condenser and uni-directional conductors interposed in the relay-to-condenser charging circult also in the condenser-to-selective means dischargmg c1rcu1t whereby improper feed-back of current through the said charging and discharging circuits is duly prevented. N

11. In a communications system, a line relay, a condenser, a time element difierentiating relay comprising a plurality of energizing coils, namely an operating coil, a retard coil, a biasing coil and a slow-release coil selective means electrically connected to receive the discharged energy from said condenser anda conductor whereby part ,of the energy discharged is shunted through the slow-release coil if said time element difierentiating relayis actuated. v

12. In a communications system, the combination of a line'relay having marking and spacing contacts, a source of current, a time element differentiating relay having operating, retard and biasing windings and a pair;

of fixed contacts and a movable contact there.-

- between, the biasing winding normally holding the movable contact-against one of the fixed contacts when the line relay marking contact is closed, a condenser in series with the retard winding, means 'for completing a circuit from the source of current through the retard and operating windings in differential relation and simultaneously charging the condenser when the line relay spacing contact closes in response toeither a dot or a dash signal, and a Work circuit connected to one of the fixed contacts and through which the condenser is discharged in response to a dot signal.

- 13. The combination according to claim 12 characterized by a work circuit connected to theother fixed contact and through which the condenser is discharged in response to a dash signal.

14. The combination according toclaim 12 characterized by an adjustable resistance in the charging circuit of the condenser.

15. In a communications system, the combination of a line relay, a step-by-step selector, means controlled by the line relay in response to a signal of at least a predetermined length to cause the selector to advance one step, a signal duration difierntiating relay brought under control of the line relay by such one step movement of the selector and thereafter cooperating with the line relay in response to a code combination of difi'erentialted signals to control the movement of the selector. I

16. In a system according to claim 1, wherein an operating circuit for the slow-to-operate'relay includes a contact of the switch closed in only the normal position'of the switch.

'17. In a system according to claim 1, wherein means actuated by the switch in taking its first step puts the receptive means under control of the line relay.

18. In a communications system, the combination of a line relay, a step-by-step selector having an operating magnet, means controlled by the line relay in response to 'a first signal to cause the operating magnet. to advance the selector one step from normal po-.

sition, and means thereafter cooperating with the line relay in response to a predetermined combination of signals to cause theoperating magnet to advancethe selector. step by step.

19. In a system according to claim 18 characterized in this that the selector has a r estoring magnet, and said second mentioned means cooperates with the line relay in response to a difi'erent combination of signals to cause the operation of the restoring magnet to reset the selector to normal position.

In witness whereof, I hereunto subscribe my name this 22nd day of April, 1930;

RALPH W. BUMSTEAD. 

